Wind Turbine Comprising a Multiplied Redundancy Control System and Method of Controlling a Wind Turbine

ABSTRACT

A wind turbine ( 1 ) comprising equipment under control is presented, which comprises at least one control system ( 14, 14 A,  14 B) for one or more of said main components, ( 5, 7, 9 ) of the wind turbine. The control system ( 14 A) is multiplied by at least one further control system ( 14 B) for controlling the same of said equipment under control. A control arrangement, a method as well as uses hereof are also presented.

BACKGROUND OF THE INVENTION

The invention relates to a wind turbine according to the preamble ofclaim 1, a control arrangement, a method of controlling a control systembeing multiplied by at least one further control system for controllingthe same equipment under control of a wind turbine and uses hereof.

DESCRIPTION OF THE RELATED ART

Wind turbines are designed to face harsh and changing weather in a longperiod of years and still show a high dependability. Previously, thedependability has been achieved by designing wind turbines with acertain over-sizing in relation to the required under normal use of thewind turbine.

The tower, wind turbine blades and breaking systems may for example beover-sized in order to handle extreme weather situation or excessiveforces during a malfunction such as loss of utility grid or control ofthe wind turbine rotor.

However, it is an increasing challenge to transport and handle the windturbine components of large modern wind turbines. Consequently, theover-sized components are a significant problem in relation to size andweight during transport and handling as well as expensive in materialcosts.

Previously, it has also been known to have more than one component of akind in a wind turbine. The redundancy is especially used with thecomponents which face significant mechanical stress e.g. a hydraulicpitch actuator. The extra component may take on the workload in a shortperiod after a main component has failed until the repair people arriveand thus enhances the availability and dependability of the windturbine. However, the more than one component of a kind does not changeor solve the above-mentioned problem regarding size and weight as wellas material costs of wind turbine components.

An object of the invention is to establish technique allowing moreweight- and cost-efficient wind turbines to be built.

THE INVENTION

The invention relates to a wind turbine where the control system ismultiplied by at least one further control system for controlling thesame of said equipment under control.

Hereby is established a wind turbine without the above-mentioneddisadvantages of the prior art. The elimination of single points offailure possibility in the control of equipment under control bysecuring the functionality on system level is advantageous. With theenhancing of the safety level and thus the reliability of the windturbine it is possible to design the different wind turbine componentsto normal use and fatigue instead of designing for extreme loads.

The wind turbine tower may for example be designed with a “normal sized”material tightness as risk of malfunctions such as the risk of dangerousrotor overspeed due to loss of control is significantly diminished. Thesaved materials of a “normal sized” tower and other structuralcomponents of the wind turbine may exceed 25%.

The term “equipment under control” and “main components” shouldespecially be understood as the wind turbine blades, gear (if any) andgenerator of the wind turbine.

The term “control system” should be understood as a system supervisingand controlling a main component and including the necessary componentsin doing so.

In an aspect of the invention, said equipment under control being maincomponents of the wind turbine such as the wind turbine blades.

In an aspect of the invention, said control systems being operatingsimultaneously and independently of each other. Hereby it is possible tocontinuously control the main component regardless that one controlsystem fails. The wind turbine may thus continue to generate power untilreplacement of the failed system can be performed or be shut down in acontrolled manner.

In an aspect of the invention, said control systems being operatingsimultaneously with dependent supervision of each other. Hereby, it isensured that the control systems work together in an advantageouslycontrol of a main component.

In an aspect of the invention, said equipment under control comprises atleast one pitch or active stall wind turbine blade. It is advantageousto use the invention in connection with large wind turbine blades as thepitch mechanism of each blade also is the only brake system of therotor.

In an aspect of the invention, said at least one wind turbine blade ispart of a wind turbine with two or three blades. It is especiallyadvantageous to use the invention in connection with two-bladed windturbines as loss of control in one blade may result in loss of theability to stop the wind turbine rotor as such.

In an aspect of the invention, said wind turbine comprises a teetermechanism including teeter angle sensors.

In an aspect of the invention, said control systems include thesupervision systems for said pitch or active stall wind turbine blades.

In an aspect of the invention, one of said control systems comprisespitch and/or teeter components e.g. sensors such as blade load sensors,pitch position sensors, azimuth sensors and/or teeter angle sensors,actuators such as pitch actuators and/or teeter actuators, powersupplies including UPS and/or controllers such as microcomputers. Herebyit is ensured that any type of failure is not fatal as the components ofthe system is multiplied and consequently that the one or more remainingcontrol systems may continue the normal control of the wind turbine orat least stop the wind turbine in a controlled manner.

In an aspect of the invention, sensors in one of said control system arepositioned differently in relation to the positions of the correspondingsensors in further of said control systems. Hereby it is ensured thatdamage to a section of the wind turbine component such as a pitch windturbine blade e.g. by a stroke of lightning at sensors of the controlsystem does not automatically affect the sensors of the further controlsystem.

In an aspect of the invention, the wind turbine comprises more than twocontrol systems e.g. three or four control systems. The number offurther control systems may be chosen by the risk of damage to thesystem in order to achieve the necessary reliability of the windturbine. The number may for example be chosen by the type of windturbine, two or three-bladed, the place of erecting the wind turbine,frequent lightning storms, and the accessibility of the wind turbinee.g. an off-shore wind turbine.

In an aspect of the invention, the wind turbine comprises at least twocontrol systems wherein one or more components of said systems aremultiplied by at least two or three such as more than two pitchcomponents, teeter components and/or controllers.

In an aspect of the invention, said control systems include a number ofcentral controllers. Hereby, it is easier to position the controllers ina protected and safe environment.

In an aspect of the invention, said control systems include a number ofdistributed controllers e.g. controllers distributed at the wind turbinehub, the main shaft, the root of the wind turbine blade and/or insidethe blade. Hereby, it is possible to enhance the reliability of thecontrol systems as they may continue working if distributed controllersof one equipment under control fail. The distributed controllers ofother equipment under control may take over the control from the failedcontrollers e.g. the controllers of one blade may control the controlsystems of two blades due to a failure in the controllers of one bladecaused by a stroke of lightning in the blade.

In an aspect of the invention, said control systems are connected bycables such as individual cables between the components. Hereby areestablished separate connection circuits between the different sets andthus enhancing the high reliability of the control systems even further.

In an aspect of the invention, control systems are connected by acommunication bus system e.g. using copper cables and/or fiber opticcommunication cables, radio and/or wireless communication connectionssuch as bluetooth connections. The use of separate connection circuits,fiber optic communication cables and/or wireless communicationespecially ensures a higher reliability against malfunction after astroke of lightning.

In an aspect of the invention, said control systems being partly orfully identical systems. Hereby, it is possible to enhance the commonsafety level of the control systems.

In an aspect of the invention, said control systems being a multipliedredundancy system. Hereby is an advantageous embodiment of the inventionachieved.

The invention also relates to a control arrangement for a wind turbinerotor including at least two wind turbine blades, wherein saidarrangement comprises a plurality of control systems for controlling thesame wind turbine blade or the same part of the wind turbine blade,wherein at least controllers of said plurality of control systems aredistributed at the wind turbine blade or the same part of the windturbine blade being controlled, and wherein said control systems areconnected.

Hereby, it is possible to enhance the safety of the control of the windturbine rotor as the arrangement includes distributed but connectedcontrollers whereby the control arrangement may continue controlling thewind turbine blades regardless of failure in one or more controllers.

In an aspect of the invention, said controllers include one or moremicroprocessors.

In an aspect of the invention, said control systems are connected by acommunication bus system e.g. using copper cables and/or fiber opticcommunication cables, radio and/or wireless communication connectionssuch as bluetooth connections. The bus system ensures that any data maybe shared among the control systems and the controllers. Hereby, it isensured that any blade in the wind turbine rotor may remain undercontrol regardless of failure in some of the control systems andcontrollers.

In an aspect of the invention, said controllers are distributed at thewind turbine hub, the main shaft, the root of the wind turbine bladeand/or inside the blade. By positioning the controllers locally inproximity of the equipment under control a simpler and more reliableconstruction of a control arrangement is achieved.

The invention also relates to a method of controlling a control systembeing multiplied by at least one further control system for controllingthe same equipment under control of a wind turbine according to any ofclaims 1 to 18.

In aspects of the invention, said control systems are operatedsimultaneously and independently of each other or in dependency of eachother by exchanging control communication. Hereby are advantageousembodiments of the invention achieved.

In an aspect of the invention, control communication is transferred on acommunication bus system connecting said control systems. In a furtheraspect of the invention, said communication is transferred on acommunication bus system between central or distributed controllers.Hereby are advantageous embodiments of the invention achieved.

The invention also relates to uses of a wind turbine, controlarrangement and method in connection with emergency stop of the windturbine during extreme situations such as weather situations or loss ofa utility grid.

FIGURES

The invention will be described in the following with reference to thefigures in which

FIG. 1 illustrates a large modern wind turbine including three windturbine blades in the wind turbine rotor,

FIG. 2 illustrates schematically a section of a wind turbine accordingto the invention,

FIG. 3 illustrates schematically a central control system of athree-bladed wind turbine,

FIG. 4 illustrates the control system of FIG. 3 in further details,

FIG. 5 illustrates the control system of FIG. 3 in details for a twobladed wind turbine,

FIG. 6 illustrates schematically a control arrangement includingdistributed control systems of a three-bladed wind turbine,

FIG. 7 illustrates the control arrangement including distributed controlsystems of a two-bladed wind turbine in details, and

FIG. 8 illustrates another embodiment of the control arrangementincluding distributed control systems of a two-bladed wind turbine.

DETAILED DESCRIPTION

FIG. 1 illustrates a modern wind turbine 1 with a tower 2 and a windturbine nacelle 3 positioned on top of the tower. The blades 5 of thewind turbine rotor are connected to the nacelle through the low speedshaft which extends out of the nacelle front.

As illustrated in the figure, wind over a certain level will activatethe rotor and allow it to rotate in a perpendicular direction to thewind. The rotation movement is converted to electric power which usuallyis supplied to the transmission grid as will be known by skilled personswithin the area.

FIG. 2 illustrates schematically the equipment under control, i.e. thewind turbine blades 5, the gear 9, and the electric generator 7. Theequipment under control are supervised and controlled by control systems14 of a wind turbine according to the invention. The wind turbinefurther comprises the low and high speed shafts 10, 8 connecting thewind turbine blades 5, the gear 9, and the electric generator 7. Teetermechanism allows the wind turbine blades to be angled in relation to avertical plane.

The control systems 14 may supervise and control any of the equipmentunder control, such as the wind turbine blades 5, during normal use andstopping of the wind turbine.

According to the invention the control systems 14 comprise a firstcontrol system 14A which is multiplied by at least one further controlsystem 14B for supervising and controlling the same equipment undercontrol.

The control systems 14A, 14B are preferably identical systems inconstruction and performing the same functionality. They may operatesimultaneously and independently of each other in supervising andcontrolling the same equipment under control.

FIG. 3 illustrates schematically a central control system of athree-bladed wind turbine.

The figure illustrates how the wind turbine blades are centrallycontrolled from control systems wherein communication between componentsin the control systems and the blades are performed on a communicationbus. The communication bus may be wired connections e.g. a communicationbus system using copper cables and/or fiber optic communication cables.Further, the communication bus may include radio and/or wirelesscommunication connections such as bluetooth connections between thecontrol systems. The communication bus may for example use standard LANtechnique.

The connection between the individual components of the control systemsand the blades may be established by separate or common cables e.g.separate power cables transferring power to each relevant component.

FIG. 4 illustrates the central control system of FIG. 3 in furtherdetails wherein the control systems 14A, 14B are part of a three-bladedwind turbine.

Each set of control systems 14A, 14B comprises one or moremicrocontroller 17, μCtrl A, μCtrl B collecting, treating andtransmitting data such as collecting data from the control systemsensors in the relevant equipment under control and transmitting controldata to control system components controlling the relevant equipmentunder control.

Examples of control system sensors and components are pitch position andblade load sensors as well as pitch actuators in relation to one windturbine blade 5. The blade arrangement is replicated in all the blades5.

Further, each set of control systems 14A, 14B may comprise an azimuthsensor 15 transmitting data to the blade microcontrollers 17.

The two microcontrollers 17 of the sets of control systems 14A, 14B arepower supplied from their own separate power supplies 16 in which eachpower supply includes an uninterruptible power supply UPS A, UPS B. Thetwo UPS power the control systems and allow the wind turbine to becontrolled and stopped at a power blackout e.g. caused by a directstroke of lightning on a power line.

The control system sensors of different sets may be positioned inproximity of each other e.g. one blade load sensor close to the nextblade load sensor but preferably not at the same position on the windturbine blade 5.

FIG. 5 illustrates the central control system of FIG. 3 in a two-bladedwind turbine.

The structure of the control systems 14A, 14B of FIG. 4 substantiallycorresponds to the systems of FIG. 4. The situation of one blade lessmay initiate the use more than two identical control systems e.g. threeor four control systems in order to enhance the security level againstthe wind turbine being damaged as a subsequent consequence of more thanone control system malfunction.

The control system according to the invention may also be used inrelation to other main components beside the wind turbine blades. Thecontrol system may for example also be used in connection withsupervising and controlling the electric generator and thus ensuringthat the generator does not face damaging work conditions as asubsequent consequence of a control system malfunction.

FIG. 6 schematically illustrates a control arrangement includingdistributed control systems of a three-bladed wind turbine.

The figure illustrates how each wind turbine blade is controlled fromcontrol systems positioned locally at each blade. The communicationbetween components in the control systems and the blades are performedon a communication bus e.g. corresponding to the communication busmentioned in connection with FIG. 3.

FIG. 7 illustrates a control arrangement including the distributedcontrol systems of a two-bladed wind turbine in details.

The figure illustrates how the control system of each blade ismultiplied e.g. in relation to sensors, controllers and power suppliesincluding UPS. The controllers are connected in a local area network LANand such may communicate and supervise each others functionality.

FIG. 8 illustrates another embodiment of the control arrangementincluding distributed control systems in a two-bladed wind turbine.

The controllers of the figure are connected by a communication bus in aLAN and as such establish multiplied controllers; controller 1,controller 2 and controller of the figure.

The wind turbine according to the invention may be part of a wind parkwhere every wind turbine is connected to a central control station thatresponds to failure messages from the wind turbines such as a failedcontrol system e.g. by sending maintenance people or a stop signal tothe wind turbine.

The invention has been exemplified above with reference to specificexamples of a wind turbine with control systems. The system may controlthe wind turbine in use or during a stopping process at a malfunction ofone control system e.g. an emergency stop. However, it should beunderstood that the invention is not limited to the particular examplesdescribed above but may be designed and altered in a multitude ofvarieties within the scope of the invention as specified in the claims.

1. Wind turbine comprising: equipment under control; and a controlsystem for one or more of said equipment under control; wherein saidcontrol system being multiplied by at least one further control systemfor controlling the same of said equipment under control and saidcontrol systems being connected by a communication bus system.
 2. Windturbine according to claim 1, wherein said equipment under control beingmain components of the wind turbine.
 3. Wind turbine according to claim1, wherein said control systems being operating simultaneously andindependently of each other.
 4. Wind turbine according to claim 1,wherein said control systems being operating simultaneously withdependent supervision of each other.
 5. Wind turbine according to claim1, wherein said equipment under control comprise at least one pitch oractive stall wind turbine blade.
 6. Wind turbine according to claim 5,wherein said at least one wind turbine blade is part of a wind turbinewith two or three blades.
 7. Wind turbine according to claim 5, whereinsaid control systems include supervision systems for said pitch oractive stall wind turbine blades.
 8. Wind turbine according to claim 1,wherein said wind turbine comprises a teeter mechanism including teeterangle sensors.
 9. Wind turbine according to claim 1, wherein one of saidcontrol systems comprises pitch and/or teeter components comprisingsensors including blade load sensors, pitch position sensors, azimuthsensors and/or teeter angle sensors, actuators including pitch actuatorsand/or teeter actuators, power supplies including UPS and/or controllerssuch as microcomputers.
 10. Wind turbine according to claim 9, whereinsensors in one of said control system are positioned differently inrelation to positions of corresponding sensors in said further controlsystem.
 11. Wind turbine according to claim 1, wherein the wind turbinecomprises more than said two control systems.
 12. Wind turbine accordingto claim 1, wherein the wind turbine comprises at least two said controlsystems wherein one or more components of said systems are multiplied byat least two pitch components, teeter components and/or controllers. 13.Wind turbine according to claim 1, wherein said control systems includea number of central controllers.
 14. Wind turbine according to claim 1,wherein said control systems include a number of distributed controllersdistributed at a wind turbine hub, a main shaft, a root of the windturbine blade and/or inside a blade.
 15. Wind turbine according to claim2, wherein said control systems are connected by cables comprisingindividual cables between the components.
 16. Wind turbine according toclaim 1, wherein said control systems are connected by the communicationbus system using copper cables and/or fiber optic communication cables,radio and/or wireless communication connections.
 17. Wind turbineaccording to claim 1, wherein said control systems being partly or fullyidentical systems.
 18. Wind turbine according to claim 1, wherein saidcontrol systems being a multiplied redundancy system.
 19. Controlarrangement for a wind turbine rotor including at least two wind turbineblades, wherein said arrangement comprises: a plurality of controlsystems for controlling the same wind turbine blade or the same part ofthe wind turbine blade; wherein at least controllers of said pluralityof control systems are distributed at the wind turbine blade or the samepart of the wind turbine blade being controlled; and wherein saidcontrol systems are connected by a communication bus system.
 20. Controlarrangement according to claim 19, wherein said controllers include oneor more microprocessors.
 21. Control arrangement according to claim 19,wherein said control systems are connected by the communication bussystem using copper cables and/or fiber optic communication cables,radio and/or wireless communication connections.
 22. Control arrangementaccording to claim 19, wherein said controllers are distributed at awind turbine hub, a main shaft, a root of the wind turbine blade and/orinside the blade.
 23. Method of controlling a control system beingmultiplied by at least one further control system for controlling thesame equipment under control of a wind turbine according to claim
 1. 24.Method according to claim 23 where said control systems are operatedsimultaneously and independently of each other.
 25. Method according toclaim 23 where said control systems are operating simultaneously and independency of each other by exchanging control communication.
 26. Methodaccording claim 23 where control communication is transferred on acommunication bus system connecting said control systems.
 27. Methodaccording to claim 26 where said communication is transferred on acommunication bus system between central or distributed controllers. 28.Wind turbine according to claim 1, wherein said control systems beingconfigured to provide for an emergency stop of the wind turbine duringextreme situations including weather situations or loss of a utilitygrid.
 29. Control arrangement according to claim 19, wherein saidcontrol systems being configured to provide for an emergency stop of thewind turbine during extreme situations such as weather situations orloss of a utility grid.
 30. Method according to claim 23, furthercomprising emergency stopping of a wind turbine by said control systemsduring extreme situations including weather situations or loss of autility grid.